The present invention relates generally to opener assemblies for forming a trench and depositing seed or fertizer therein, and more specifically, to a disk blade opener for conservation tillage applications where trash and/or stubble and the like are present or the surface of the ground.
Conservation tillage practices have become more widespread in recent years, and are utilized to conserve moisture, prevent erosion, and reduce the number of trips over the field. With such practices, the amount of trash and residue left on the soil surface is increased. Ideally the amount of soil moved during the seeding or fertilizing operation is minimized to prevent disturbance of any chemicals that have been applied and reduce plugging problems which are aggravated by the trash, particularly when the opener devices are narrowly spaced.
Commercially available conversation tillage grain drills such as the Moore Uni-Drill utilize large disk openers which are mounted on either side of a drag arm at opposite angles and are inclined both in the horizontal and vertical planes to slice through surface residue and open a slit in the soil. A seed tube coulter holds the slit open while seeds are dropped into the seed bed formed in the slit. Such a drill utilizes a weight transfer system to control the depth of the slit, and therefore depth control and seed placement can vary substantially with varying soil characteristics. In certain conditions, soil can be thrown from the side of the disk, adversely effecting seed planting characteristics, particularly when narrow row spacings are utilized.
Other single disk type of openers have been utilized to form a furrow in the soil, but most suffer from some disadvantages when utilized in conversation tillage applications. Devices such as shown in U.S. Pats. Nos. 4,031,834 and 2,869,489 utilize boot or shoe structures which extend rearwardly behind the disk and increase trash and side bend problems. These devices and other ones such as shown in U.S. Pat. No. 1,940,273 also utilize concave disks which tend to throw more soil. Concave disks have more difficulty slicing through thick trash, and precise depth control is a problem. In other structures such as shown in U.S. Pat. No. 2,920,587 a flat seed furrow opening disk is utilized in combination with a flat fertilizer opening disk, and depth control is provided by a band attached to the fertilizer disk. In such a structure, gauging can be less than optimum since the gauge band is offset from the seed furrow opening disk. The band is not adjustable to vary the depth of penetration of the fertilizer disk, and scrapers are necessary to keep the band clean for proper depth gauging action. Such a disk arrangement also disturbs more soil, thus causing more potential trash problems as well as decreasing the amount of moisture maintained in the soil.